JERUSALEM, (Reuters) – A fourth dose of COVID-19 vaccine increases antibodies to higher levels than the previous jab. However it does not prevent Omicron infection according to preliminary Israeli research.

Israel’s Sheba Medical Center administered second booster shots during a pilot study among staff members. It is currently studying the results of the procedure. Pfizer (NYSE:) Boost in 154 People After Two Weeks and The Moderna (NASDAQ:) boost in 120 people within one week of each other, according to Gili RegevYochay director, Infectious Diseases Unit.

They were then compared with a group who did not get the fourth shot. The hospital stated that the Moderna group previously had three shots of Pfizer’s vaccine.

Regev-Yochay stated that the vaccines caused an increase in antibodies, “even slightly higher than what was after the third dose.”

Reporters were told by her that this was not enough to protect Omicron. We know that Omicron vaccines don’t have enough antibodies to prevent infection.

According to the hospital, the findings are the first ever of their kind worldwide. However, they were not published yet.

Israel, which was first to offer COVID-19 vaccinations a year earlier, has now begun offering the fourth, or second booster, to those most at-risk.